From 9e2ff6c9cc54c0b4402b8d49e4abe7000fde7617 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Mon, 8 Aug 2016 09:29:18 +0200 Subject: [PATCH] arm: mark __startcontext as .cantunwind (bug 20435) __startcontext marks the bottom of the call stack of the contexts created by makecontext. --- ChangeLog | 6 ++++++ sysdeps/unix/sysv/linux/arm/setcontext.S | 7 +++++++ 2 files changed, 13 insertions(+) diff --git a/ChangeLog b/ChangeLog index 1e35b52ea2..62f60dceea 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2016-08-15 Andreas Schwab + + [BZ #20435] + * sysdeps/unix/sysv/linux/arm/setcontext.S (__startcontext): Mark + as .cantunwind. + 2016-08-12 Joseph Myers * sysdeps/powerpc/fpu/fsetexcptflg.c (__fesetexceptflag): Add diff --git a/sysdeps/unix/sysv/linux/arm/setcontext.S b/sysdeps/unix/sysv/linux/arm/setcontext.S index 603e508858..d1f168fece 100644 --- a/sysdeps/unix/sysv/linux/arm/setcontext.S +++ b/sysdeps/unix/sysv/linux/arm/setcontext.S @@ -86,12 +86,19 @@ weak_alias(__setcontext, setcontext) /* Called when a makecontext() context returns. Start the context in R4 or fall through to exit(). */ + /* Unwind descriptors are looked up based on PC - 2, so we have to + make sure to mark the instruction preceding the __startcontext + label as .cantunwind. */ + .fnstart + .cantunwind + nop ENTRY(__startcontext) movs r0, r4 bne PLTJMP(__setcontext) @ New context was 0 - exit b PLTJMP(HIDDEN_JUMPTARGET(exit)) + .fnend END(__startcontext) #ifdef PIC